The present invention relates to a passenger-side airbag device installed in an instrument panel in front of a passenger""s seat of a vehicle including an automobile.
A passenger-side airbag device comprises a container installed in an instrument panel in front of a passenger""s seat of a vehicle, a gas generator for inflating an airbag, an airbag accommodated in the container and having a gas inlet for receiving gas, and a lid covering the container. The gas generator is actuated to supply gas into the airbag when the vehicle comes into collision, and the airbag starts to expand. After the airbag starts expanding, the lid is pushed by the airbag and opens whereby the airbag inflates into a vehicle cabin.
The airbag has a gas inlet for receiving gas from the gas generator. The periphery of the gas inlet is connected to the container.
The airbag is folded, as described in JPA-4-100754, by first tucking a left side and a right side of the airbag therein toward the center to make the airbag a semi-folded body in which the width along the lateral direction is small, then folding the semi-folded body into a bellows-like configuration to form a bulk portion, and accommodating the bulk portion in the container.
Hereinafter, the folding manner of the airbag of JPA 4-100754 will be described with reference to FIGS. 6 through 12.
FIG. 6 is a perspective view of an airbag 1 in its flat-spreaded state and a sub-container 2. The airbag 1 has short sides 1b which are straight, long right and left sides la which are curved in an arc shape, a gas inlet 3 for receiving gas from an inflator which is formed at a center of a rear face opposite to a front face to confront an occupant, and vent holes 4 for buffering when the occupant collides with the inflated airbag. A reference numeral 5 designates a rivet hole. The sub-container 2 is provided with holes 6 formed at a bottom thereof through which gas from the inflator passes into the airbag 1.
The airbag 1 is flat spread that the sub-container 2 is connected to the airbag 1 as shown in FIG. 7. From this state, the long sides 1a are tucked in the airbag 1 in such a manner that the width of the airbag 1 becomes slightly smaller than the width of the sub-container, thereby forming a semi-folded body as shown in FIG. 8 and FIG. 9 which is a sectional view taken along a line IXxe2x80x94IX of FIG. 8.
Then, the semi-folded body 1 is folded many times in bellows like configuration so as to crease pleat lines 7 extending perpendicularly to straight sides 1axe2x80x2 of the semi-folded body as shown in FIG. 10 which is a side view taken along a line Xxe2x80x94X of FIG. 8. As shown in FIG. 11, the folded portions are piled up and accommodated in the sub-container 2 (FIG. 12).
Though the folded airbag is accommodated in the sub-container 2 and the sub-container 2 is accommodated in a main container (not shown) in JPA 4-100754, the folded airbag is sometimes directly accommodated in the main container without the sub-container.
In the conventional passenger-side airbag device, a bulk body of the airbag is formed by folding the airbag 1. The periphery of the gas inlet 3 of the airbag 1 is connected to the sub-container 2. Among portions around the periphery of the gas inlet 3 of the airbag 1, a windshield-side portion 1A, which is connected to a windshield side 2A of the sub-container 2, has the same length as that of an occupant-side portion 1B, which is connected to an occupant side 2B of the sub-container 2.
Therefore, when the airbag 1 is about to be inflated (deployed) with gas from the inflator, the airbag 1 starts to expand in a direction perpendicular to the upper surface of the sub-container 2 as shown by an arrow S of FIG. 12. Since the sub-container 2 is disposed such that the upper surface thereof is parallel to a panel surface of the instrument panel, the airbag 1 starts to expand in a direction perpendicular to the panel surface of the instrument panel. In case conventional passenger-side airbag device, in which the airbag will start to expand in the direction perpendicular to the panel surface of the instrument panel, is installed in a portion of the upper surface side of the instrument panel, when the airbag collides with the windshield during its expansion so the airbag is subjected to forces such as friction from the windshield. Because of this situation, it is necessary, for inflating sufficiently the airbag, to supply high-pressure gas into the airbag to overcome the forces such as friction. Therefore, a gas generator of large capacity is required.
It is an object of the invention to provide a passenger-side airbag device in which an airbag is hard to collide with a windshield during its deployment even when the airbag device is disposed in an upper-side portion of an instrument panel.
A passenger-side airbag device of the present invention comprises a container installed in an instrument panel in front of a passenger seat, a gas generator for inflating an airbag, and an airbag accommodated in the container and having a gas inlet for receiving gas. The periphery of the gas inlet is connected to the container. The airbag has a bulk portion formed by folding and a peripheral area between the bulk portion and the gas inlet. The length L1 of the peripheral area between the windshield side of the container and the bulk portion is longer than the length L2 of the peripheral area between the occupant side of the container and the bulk portion.
When a vehicle, in which the passenger-side airbag device is installed in the upper surface of the instrument panel, comes into collision and the gas generator is actuated, the airbag pushes outwardly the lid to open the lid and starts to expand into the vehicle cabin.
In this case, the bulk portion is moved to the upper side of the instrument panel and then the bulk portion is gradually inflated. Since the length L1 of the windshield-side peripheral area is longer than the length L2 of the occupant-side peripheral area, the bulk portion is moved in a direction apart from the windshield not in a direction perpendicular to the panel surface of the instrument panel. As a result, the airbag during its deployment is hard to collide (or does not collide at all) with the windshield.
It is preferable that the length L1 is 1.5-4 times, particularly 1.5-3 times, more particularly 2-2.5 times longer than the length L2.
According to the present invention, the airbag is preferably folded by first tucking a left side and a right side of the airbag therein toward the center to make the airbag a semi-folded body having a smaller width along the lateral direction, and then concavely folding a portion, to be confronting an occupant in the passenger seat, of the semi-folded body.
It should be understood that the right and left of the airbag means the right and left from the view point of the occupant when the passenger-side airbag device is installed in the vehicle and the occupant is oriented toward the front of the vehicle.